CN112030251A - A kind of whole cellulose nanocomposite fiber and preparation method thereof - Google Patents

Abstract

The invention discloses a preparation method of whole cellulose nanocomposite fibers, which comprises the following steps: grinding and centrifuging a microcrystalline cellulose suspension to obtain a supernatant of cellulose nanocrystals; adding the supernatant of cellulose nanocrystals to Mix evenly in the cellulose fiber spinning stock solution, and spin the cellulose nanocrystal/cellulose fiber spinning stock solution after removing the bubbles. The length of the cellulose nanocrystal in the supernatant is 223±100nm～ 366±171nm, and its diameter is 29±8nm～35±9nm. The invention can make the dispersion of cellulose nanocrystals in the cellulose fiber spinning stock solution uniform, improve the dispersion stability of cellulose nanocrystals in the spinning stock solution, avoid the re-aggregation of cellulose nanocrystals, and make the cellulose nanocrystals It can be uniformly dispersed in the spinning dope, and finally improve the mechanical properties of the composite fiber.

Description

A kind of whole cellulose nanocomposite fiber and preparation method thereof

technical field

The invention relates to the field of all-cellulose nanocomposite fibers, in particular to an all-cellulose nanocomposite fiber and a preparation method thereof.

Background technique

Composite materials are a class of materials that consist of two or more distinct components with significantly different physical and/or chemical properties. The resulting composite material may have enhanced mechanical properties (relative to the mechanical properties of the matrix) and/or new functionalities (eg barrier properties). Typically, composite materials contain a strong and hard component, the reinforcement, embedded in a matrix of softer (relative to the reinforcement) components. In this way, the strength properties of the composite material are intermediate between the reinforcement and the matrix. Reinforcements in composite materials can be structurally divided into: woven fabrics, continuous fibers, short fibers and particulate matter, or morphologically classified into macroscopic, microscopic or nanoscale according to their physical dimensions. At present, nano-reinforcement has become a hot focus of reinforced composite materials due to its own properties.

Viscose fiber is one of the most important regenerated cellulose fibers. Fabrics made with viscose are soft, smooth, cool, breathable, antistatic and colorful. These unique properties make it widely used in underwear, textiles, apparel and carpets (Morton and Beaumont 1960). Ordinary viscose fiber has poor dimensional stability under humid conditions due to its low crystallinity, and its mechanical properties are seriously reduced. Therefore, how to obtain viscose fibers with high strength and low elongation at break has been a hot research topic for a long time. Generally speaking, adding reinforcements to obtain composite fibers is the simplest and most effective method to improve the mechanical and physical properties of fibers. Cellulose nanocrystals have a perfect crystal structure and large specific surface area, and theoretically predicted elastic modulus and tensile strength of 150 and 10 GPa (Sakurada and Nukushina 1962), which are comparable to aramid fibers (Kevlar), are a Enhancer with good physico-mechanical properties. In addition, cellulose nanocrystals have the same chemical composition as viscose fibers (matrix), both of which are cellulose and have good compatibility. Therefore, the whole cellulose nanocomposite fibers composed of them are more and more popular (Missio et al. al. 2018).

At present, in the process of preparing nanocomposite fibers, there is a problem that nanomaterials are not easy to disperse uniformly in the polymer matrix, and are prone to unstable dispersion, which eventually leads to the decline of the physical properties of the composite material products and the inability to achieve the desired mechanical strength. For example, the patent "a preparation method of high-strength viscose fiber (CN103255488B)" adopts the method of secondary mechanical stirring to disperse nano-whiskers to improve the dispersibility of nano-whiskers in viscose solution, but in fact, due to the mechanical agitation In fact, dispersion is only an auxiliary dispersion method, and it is difficult to overcome the self-aggregation effect of nanowhiskers.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned problems, the purpose of the present invention is to provide a preparation method of whole cellulose nanocomposite fibers. The dispersion of the nanocrystals in the cellulose fiber spinning stock solution is uniform, and the dispersion stability of the cellulose nanocrystals in the cellulose fiber spinning stock solution is improved, and the mechanical strength of the nanocomposite is effectively enhanced.

The present invention is achieved through the following technical solutions:

A method for preparing whole cellulose nanocomposite fibers, comprising the following steps: grinding and centrifuging a microcrystalline cellulose suspension to obtain a cellulose nanocrystal supernatant, adding the cellulose nanocrystal supernatant to cellulose The fiber spinning stock solution is mixed evenly, and the uniformly mixed cellulose nanocrystal/cellulose fiber spinning stock solution is de-bubbled and then spun, wherein the length of the cellulose nanocrystal in the supernatant is 223±100nm～366±171nm , its diameter is 29±8nm～35±9nm.

Different from the prior art, the present invention adopts the mechanical method to discard the solid precipitation microcrystalline cellulose after grinding and centrifuging the microcrystalline cellulose, and selects the supernatant liquid containing the cellulose nanocrystals of appropriate size, so that the cellulose is removed. The nanocrystal supernatant is added to the spinning stock solution, and after mixing evenly, the dispersion of cellulose nanocrystals in the cellulose fiber spinning stock solution can be uniform, and the dispersion stability of cellulose nanocrystals in the spinning stock solution can be improved at the same time. The re-aggregation of cellulose nanocrystals enables cellulose nanocrystals to be uniformly dispersed in the spinning dope. In addition, the use of the supernatant of cellulose nanocrystals of appropriate size can also prevent them from clogging the spinneret holes during the spinning process.

In specific practice, the microcrystalline cellulose is mixed with water and dispersed into a suspension, and the suspension is ground and centrifuged to obtain a cellulose nanocrystal supernatant. The supernatant obtained after grinding and centrifugation is a uniform and stable dispersion of cellulose nanocrystals. The suspension is ground with a colloid mill for 4-8 hours, during which the stator is tightened at appropriate intervals until the distance between the rotor and the stator reaches the minimum value. Appropriate time such as 20min, 30min and so on. The solids content of microcrystalline cellulose in the suspension is 1-5%. In order to ensure the grinding effect, the microcrystalline cellulose is effectively dispersed, homogenized and pulverized through the strong shearing force, frictional force, high-frequency vibration, high-speed vortex and other physical effects generated by the colloid mill, so as to achieve the dissociation of the microcrystalline cellulose. The effect of forming cellulose nanocrystals. High solids content is not conducive to dispersion and grinding.

Centrifugal speed is 2000-4000 rpm in centrifugation. Further, in the centrifugal separation, the centrifugal speed is 4000 rev/min.

In practice, the raw material microcrystalline cellulose is a commercially available commodity, and its sources are wide. It can be obtained by acid hydrolysis of biomass materials such as wood pulp, cotton pulp, bamboo pulp, ramie, and straw, such as sulfuric acid hydrolysis. The microcrystalline cellulose suspension is subjected to a colloid mill grinding process. The microcrystalline cellulose obtained by acid hydrolysis, after grinding and centrifugation, the surface of cellulose nanocrystals has an appropriate charge, and the Zeta potential test of the supernatant dispersion shows that the surface of cellulose nanocrystals has a negative charge. The smaller the size of cellulose nanocrystals, the larger the specific surface area and the larger the surface charge density. The greater the charge density, the greater the repulsion between particles and the better the dispersibility. In the supernatant obtained after grinding and centrifugation, the size of cellulose nanocrystals is small, so the supernatant is a uniform and stable dispersion of cellulose nanocrystals.

Further, before mixing the cellulose nanocrystal supernatant into the cellulose fiber spinning stock solution, vacuum concentration at 40-60 ° C, so that the solid content of the cellulose nanocrystal in the cellulose nanocrystal supernatant is 5-10%. . The purpose of vacuum concentration is to reduce the fluctuation of dope concentration caused by the increase of volume after addition. When the cellulose nanocrystal supernatant dispersion is added as a reinforcement additive to the cellulose fiber spinning solution, if the concentration fluctuates greatly, the spinnability will be affected, and it will even fail to spin.

Among them, the mass of cellulose nanocrystals is 1-5% of the mass of cellulose in the cellulose fiber spinning dope.

Further, the homogeneously mixed cellulose nanocrystal/cellulose fiber spinning stock solution was placed under vacuum at 0° C. for 12-18 hours, and spinning was performed after removing air bubbles.

Further, the homogeneously mixed cellulose nanocrystal/cellulose fiber spinning stock solution was placed under vacuum at 0°C for 12 hours. In the wet spinning process, the coagulation bath of the present invention is composed of zinc sulfate (12-15 g/L), sodium sulfate (220-240 g/L) and sulfuric acid (115-120 g/L).

The mass fraction of cellulose in the cellulose fiber spinning solution is 8-10%, the mass of cellulose nanocrystals is 1-5% of cellulose, and the mass fraction of sodium hydroxide is 15-24%. During the spinning process, the final product showed an unexpected increase in physical properties, which may be due to the secondary aggregation of cellulose nanocrystals during long-term static defoaming or spinning storage. Therefore, in the present invention, the amount of sodium hydroxide in the spinning dope is different from that in the past, and its amount is greatly increased, which prevents the cellulose nanocrystals from standing and defoaming in the spinning dope or during the spinning storage process. Secondary aggregation, after this treatment, the physical properties of the final product have been effectively improved. This may be due to the mutual repulsion between cellulose nanocrystals due to the existence of charges. When added to the spinning dope, a large amount of sodium hydroxide in the spinning dope is added, and a large number of negatively charged hydroxide ions appear in the fiber. It reduces the chance of coalescence between cellulose nanocrystals, and finally enables cellulose nanocrystals to be uniformly and stably dispersed in the spinning dope, even after a long process of static defoaming and spinning storage. The cellulose nanocrystals will not undergo secondary aggregation, and in the process of filament formation, excess sodium hydroxide will continue to help the cellulose nanocrystals disperse during the reaction process. Therefore, in order to further improve the preparation method, the present invention comprehensively considers the environmental factors in the spinning process, and sets an excess of sodium hydroxide to prevent the occurrence of secondary aggregation of cellulose nanocrystals during static defoaming and spinning storage. .

All cellulose nanocomposite fibers obtained by the aforementioned preparation method.

In the present invention, the cellulose fibers may be viscose fibers, Lyocell fibers, Tencell fibers, cellulose acetate and the like.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. The present invention adopts the mechanical method to discard the solid precipitation microcrystalline cellulose after grinding and centrifuging the microcrystalline cellulose, and select the supernatant containing the cellulose nanocrystals of appropriate size, so that the cellulose nanocrystal supernatant is Adding it to the spinning stock solution can make the dispersion of cellulose nanocrystals in the cellulose fiber spinning stock solution uniform, improve the dispersion stability of cellulose nanocrystals in the spinning stock solution, and avoid the re-aggregation of cellulose nanocrystals. The cellulose nanocrystals can be uniformly dispersed in the spinning dope, and the spinnability and fiber quality are improved.

2. The preparation method of the present invention is simple, environmentally friendly, low in energy consumption, and easy to realize industrialization.

Description of drawings

The accompanying drawings described herein are used to provide further understanding of the embodiments of the present invention, and constitute a part of the present application, and do not constitute limitations to the embodiments of the present invention. In the attached image:

Fig. 1 is the scanning electron microscope photograph of the cross section of different cellulose nanocrystal composite viscose fibers of the present invention.

Figure 2 is a photo of the supernatant of cellulose nanocrystals with different lengths of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and the accompanying drawings. as a limitation of the present invention.

The raw materials, reagents and experimental instruments selected in the examples are all commercially available products.

Example 1

Preparation of cellulose nanocrystalline viscose fibers:

(1) First, the microcrystalline cellulose derived from wood pulp is sieved (more than 400 mesh) to remove large particles. The sieved microcrystalline cellulose was mixed with water and dispersed into a suspension with a solid content of 2%.

(2) Mill the above suspension with a colloid mill for 8 hours, during which the stator is tightened every 20 minutes until the distance between the rotor and the stator reaches the minimum value.

(3) Separating the above-ground suspension with a centrifuge to obtain a supernatant containing cellulose nanocrystals, the rotating speed of the centrifuge is 4000 rpm, and the length of the separated cellulose nanocrystals is 223±100nm, and its diameter is 223±100nm. is 29±8nm, and the aspect ratio is 8.

(4) Concentrating the above-mentioned cellulose nanocrystal supernatant under a vacuum condition of 60° C. to obtain a supernatant with a cellulose nanocrystal solid content of 5%.

(5) The concentrated cellulose nanocrystal supernatant is added to the viscose spinning stock solution as a reinforcing additive, and mixed uniformly by mechanical stirring or static mixer. The content of A-cellulose (A-fiber, α-cellulose) in the viscose spinning dope is 10%, the ratio of cellulose nanocrystals to A-fiber is 5.0%, and the mass fraction of sodium hydroxide is 24%.

(6) Put the evenly mixed cellulose nanocrystal/viscose spinning stock solution at 0°C under vacuum for 12 hours to remove air bubbles in the stock solution.

(7) Put the degassed spinning stock solution into a coagulation bath or an air bath through a metering pump and a spinneret (plate) to regenerate cellulose fibers. Then, through drawing, (washing) and drying, the cellulose nanocrystal reinforced viscose fiber is obtained. The dry tensile strength of the reinforced viscose fiber is 4.20 cN/dtex % and the wet tensile strength is 3.15 cN/dtex. This embodiment has good spinnability and uniform filaments. The coagulation bath consisted of zinc sulfate 14 g/L, sodium sulfate 230 g/L, and sulfuric acid 117 g/L.

Example 2

Preparation of cellulose nanocrystalline viscose fibers:

(1) First, the microcrystalline cellulose derived from wood pulp is sieved (more than 400 mesh) to remove large particles. The sieved microcrystalline cellulose was mixed with water and dispersed into a suspension with a solid content of 2%.

(2) Mill the above suspension with a colloid mill for 8 hours, during which the stator is tightened every 20 minutes until the distance between the rotor and the stator reaches the minimum value.

(3) Separating the above-mentioned grinding suspension with a centrifuge to obtain a supernatant containing cellulose nanocrystals, the rotating speed of the centrifuge is 3000 rpm, the length of the separated cellulose nanocrystals is 271±124nm, and the diameter is 31±9nm, the aspect ratio is 9.

(4) Concentrating the above-mentioned cellulose nanocrystal supernatant under a vacuum condition of 60° C. to obtain a supernatant with a cellulose nanocrystal solid content of 5%.

(5) The concentrated cellulose nanocrystal supernatant is added to the viscose spinning stock solution as a reinforcing additive, and mixed uniformly by mechanical stirring or static mixer. The content of A-cellulose (A-fiber, α-cellulose) in the viscose spinning dope is 10%, the ratio of cellulose nanocrystals to A-fiber is 5.0%, and the mass fraction of sodium hydroxide is 24%.

(6) Put the evenly mixed cellulose nanocrystal/viscose spinning stock solution at 0°C under vacuum for 12 hours to remove air bubbles in the stock solution.

(7) Put the degassed spinning stock solution into a coagulation bath or an air bath through a metering pump and a spinneret (plate) to regenerate cellulose fibers. Then, through drawing, (washing) and drying, the cellulose nanocrystal reinforced viscose fiber is obtained. The dry tensile strength of the reinforced viscose fiber is 3.57 cN/dtex %, and the wet tensile strength is 2.61 cN/dtex. This embodiment has good spinnability and uniform filaments. The coagulation bath consisted of zinc sulfate 14 g/L, sodium sulfate 230 g/L, and sulfuric acid 117 g/L.

Example 3

Preparation of cellulose nanocrystalline viscose fibers:

(1) First, the microcrystalline cellulose derived from wood pulp is sieved (more than 400 mesh) to remove large particles. The sieved microcrystalline cellulose was mixed with water and dispersed into a suspension with a solid content of 2%.

(2) Mill the above suspension with a colloid mill for 8 hours, during which the stator is tightened every 20 minutes until the distance between the rotor and the stator reaches the minimum value.

(3) Separating the above-mentioned grinding suspension with a centrifuge to obtain a supernatant containing cellulose nanocrystals, the speed of the centrifuge is 2000 rpm, the length of the separated cellulose nanocrystals is 366±171nm, and the diameter is 35±9nm, the aspect ratio is 10.

(4) Concentrating the above-mentioned cellulose nanocrystal supernatant under a vacuum condition of 60° C. to obtain a supernatant with a cellulose nanocrystal solid content of 5%.

(5) The concentrated cellulose nanocrystal supernatant is added to the viscose spinning stock solution as a reinforcing additive, and mixed uniformly by mechanical stirring or static mixer. The content of A-cellulose (A-fiber, α-cellulose) in the viscose spinning dope is 10%, the ratio of cellulose nanocrystals to A-fiber is 5.0%, and the mass fraction of sodium hydroxide is 24%.

(6) Put the evenly mixed cellulose nanocrystal/viscose spinning stock solution at 0°C under vacuum for 12 hours to remove air bubbles in the stock solution.

(7) Put the degassed spinning stock solution into a coagulation bath or an air bath through a metering pump and a spinneret (plate) to regenerate cellulose fibers. Then, through drawing, (washing) and drying, the cellulose nanocrystal reinforced viscose fiber is obtained. The dry tensile strength of the reinforced viscose fiber is 3.51 cN/dtex % and the wet tensile strength is 2.56 cN/dtex. This embodiment has good spinnability and uniform filaments. The coagulation bath consisted of zinc sulfate 14 g/L, sodium sulfate 230 g/L, and sulfuric acid 117 g/L.

Example 4

Similar to Example 1, the difference is that the mass ratio of cellulose nanocrystals to methyl fiber is 1.0%. The dry tensile strength of reinforced viscose fiber is 3.68 cN/dtex %, and the wet tensile strength is 2.85 cN/dtex. This embodiment has good spinnability and uniform filaments.

Example 5

Similar to Example 1, the difference is that the mass ratio of cellulose nanocrystals to methyl fiber is 4.0%. The dry tensile strength of the reinforced viscose fiber is 3.88 cN/dtex %, and the wet tensile strength is 2.85 cN/dtex. This embodiment has good spinnability and uniform filaments.

Example 6

Similar to Example 1, the difference is that the mass fraction of the added sodium hydroxide is 15%. The dry tensile strength of the reinforced viscose fiber is 3.93 cN/dtex %, and the wet tensile strength is 2.89 cN/dtex.

Example 7

Similar to Example 1, the difference is that the mass fraction of the added sodium hydroxide is 18%. The dry tensile strength of the reinforced viscose fiber is 4.05 cN/dtex % and the wet tensile strength is 3.08 cN/dtex.

Comparative Example 1

Similar to Example 1, the difference is: the length of cellulose nanocrystals is 537±197 nm, the diameter is 43±12 nm, and the aspect ratio is 12. During preparation, the spinnability is poor, and there is a phenomenon of splitting.

Comparative Example 2

Similar to Example 1, the difference is that viscose fiber spinning is performed without adding cellulose nanocrystal supernatant. The dry tensile strength is 2.21 cN/dtex %, and the wet tensile strength is 1.75 cN/dtex.

Comparative Example 3

Similar to Example 1, the difference is: the mass fraction of the added sodium hydroxide is 5%. The dry tensile strength of the reinforced viscose fiber is 2.63 cN/dtex %, and the wet tensile strength is 2.18 cN/dtex.

Comparative Example 4

Similar to Example 1, the difference is: the mass fraction of the added sodium hydroxide is 12%. The dry tensile strength of the reinforced viscose fiber is 2.77 cN/dtex % and the wet tensile strength is 2.48 cN/dtex.

In the present invention, what is not described in detail is the prior art.

Description of dispersion uniformity and stability of cellulose nanocrystals in spinning dope:

From the cross section of different cellulose nanocrystal composite viscose fibers in Figure 1 (a represents Example 1, b represents Example 2, c represents Example 3, d represents Example 6, e represents Example 7, and f represents Comparative Example 1 , g represents Comparative Example 3, and h represents Comparative Example 4). From the results of electron microscope analysis of the cross-sectional structure of the final product in Examples 1-3 and Comparative Example 1, it can be seen that the dispersion uniformity of cellulose nanocrystals is good and bad. Example 1 The dispersibility effect of cellulose nanocrystals in the composite viscose fiber is the best, and the dispersibility effect of cellulose nanocrystals in Comparative Example 1 is the worst, indicating that the method of the present invention can effectively improve cellulose nanocrystals in cellulose fiber spinning. Dispersion uniformity and stability in the original solution can obtain composite viscose fibers with uniform dispersion effect. It can be seen from the cross-sectional states of Examples 1-3, 6, and 7 that the cellulose nanocrystals are well dispersed and stable therein, while from the cross-sectional states of Comparative Examples 3 and 4, it can be seen that the cellulose nanocrystals are spun during spinning. Secondary agglomeration occurred during the process, indicating that the excessive addition of sodium hydroxide played a great role in relieving the secondary agglomeration of cellulose nanocrystals.

2 is a comparison diagram of cellulose nanocrystal supernatants with different lengths and diameters, C ₁ represents Example 1, C ₂ represents Example 2, C ₃ represents Example 3, and C ₄ represents Comparative Example 1. The smaller the particle size of cellulose nanocrystals, the larger the specific surface area and the larger the surface charge density. The charge density is large, the repulsion between particles is large, and the dispersion is good, so it is more transparent in appearance.

From the analysis of Examples 1, 4, 5 and Comparative Example 3, during wet spinning and drawing, the orientation of cellulose nanocrystals (orientation along the fiber axis) may be changed. The addition of cellulose nanocrystals in the present invention has a significant strengthening effect on the viscose filament, because after the spinning is formed, the cellulose nanocrystals are uniformly dispersed in the matrix, and the cellulose nanocrystals in the matrix pass through hydrogen. The bonds form a rigid network, and the cellulose nanocrystals have the same chemical structure and strong affinity with the matrix fibers, and the nano-scale cellulose crystals become the physical cross-linking points between the matrix cellulose molecules. When the content of cellulose nanocrystals was 5.0wt%, the mechanical properties of the fibers were the best. When the addition amount of cellulose nanocrystals exceeds 5.0 wt% (for example, 6.0 wt%), the mechanical properties of the fibers decrease, which may be due to the self-affinity agglomeration of cellulose nanocrystals, which causes the non-uniform structure of the composite fibers and weakens the fiber reinforcement effect.

In practice, the present invention is also suitable for using cellulose nanocrystal supernatant for dry spinning and preparation of other cellulose-based or cellulose-derivative-based nano-reinforced composites, such as Lyocell, Tencell Fabrication of fibers or films with fibers, cellulose acetate, etc. as a matrix.

The specific embodiments described above further describe the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a preparation method of whole cellulose nanocomposite fiber, is characterized in that, comprises the following steps: microcrystalline cellulose suspension is obtained the supernatant liquid of cellulose nanocrystal through grinding and centrifugation, and cellulose nanocrystal is supernatant. The supernatant is added to the cellulose fiber spinning stock solution and mixed evenly, and the uniformly mixed cellulose nanocrystal/cellulose fiber spinning stock solution is debubble and then spinned, wherein the length of the cellulose nanocrystal in the supernatant is 223 ±100nm～366±171nm, and its diameter is 29±8nm～35±9nm. 2. preparation method according to claim 1 is characterized in that, microcrystalline cellulose and water are mixed and dispersed into suspension, and the cellulose nanocrystal supernatant is obtained by centrifugation after the suspension is ground, and centrifugation is carried out in the centrifugation. The speed is 2000-4000 rpm. 3. preparation method according to claim 2 is characterized in that, in centrifugal separation, centrifugal rotation speed is 4000 rev/min. 4. The preparation method according to claim 2, wherein the solid content of microcrystalline cellulose in the suspension is 1-5%. 5. The preparation method according to claim 1, characterized in that, before mixing the cellulose nanocrystal supernatant into the cellulose fiber spinning stock solution, vacuum concentration at 40-60° C. makes the cellulose nanocrystal supernatant The solid content of cellulose nanocrystals is 5-10%. 6 . The preparation method according to claim 1 , wherein the uniformly mixed cellulose nanocrystal/cellulose fiber spinning stock solution is left to stand in vacuum at 0° C. for 12-15 hours. 7 . 7 . The preparation method according to claim 1 , wherein, in the cellulose fiber spinning dope, the mass fraction of cellulose is 8-10%. 8 . 8 . The preparation method according to claim 7 , wherein, in the cellulose fiber spinning dope, the mass of cellulose nanocrystals is 1-5% of the mass of cellulose. 9 . 9 . The preparation method according to claim 1 , wherein, in the cellulose fiber spinning dope, the mass fraction of sodium hydroxide is 15-24%. 10 . 10. The whole cellulose nanocomposite fiber obtained by the preparation method of any one of claims 1-9.

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